Railroad searchlight signal with solid state illuminant and aspect indication

Abstract

A railroad searchlight signal for producing light signals of selected colors. The searchlight uses a reflector that has an inner surface of reflective material and a focal point. One or more light emitting diodes are provided at the reflector focal point. When a current is supplied to the light emitting diode from a variable current power source, a light having a color that varies dependent upon the current is produced. The colored light produced at the light emitting diode is then directed outward of the reflector as a beam. At least one color filter that allows light of a respective color to pass therethrough is preferably provided proximate the reflector. Light that passes through the color filter is detected by a light detector such as a photovoltaic cell, a phototransistor or a photodiode.

What is claimed is: 
     
       1. A railroad searchlight signal for producing light signals of selected colors, said searchlight signal comprising: a reflector that is shaped generally as a truncated ellipse so as to have a rounded first end and a circular opening at a second end, said reflector also having a circular opening at said first end wherein said first end circular opening having a diameter less than that of said second end circular opening, said reflector further has an inner surface of reflective material and a focal point;   at least one light emitting diode provided through said reflector first end circular opening and positioned at said reflector focal point, wherein said at least one light emitting diode produces light when a current is supplied thereto, in which said light has a color that varies dependent upon current values; and   a variable current power source connected to said at least one light emitting diode, wherein when said at least one light emitting diode is energized by selected current values, light having colors corresponding to said current values is produced from said at least one light emitting diode and is directed outward of said reflector second end circular opening;   at least one color filter provided proximate said reflector second end, wherein each said at least one color filter allowing light of a respective color produced by said at least one light emitting diode to pass therethrough; and   a light detection means, wherein light that passes through said color filter is detected by said light detection means.   
     
     
       2. The searchlight signal of claim 1 further comprising means connected to said light detection means for generating a signal when said light detection means detects light. 
     
     
       3. The searchlight signal of claim 1 wherein said light detection means is a photovoltaic cell. 
     
     
       4. The searchlight signal of claim 1 wherein said light detection means is at least one of a phototransistor and a photodiode. 
     
     
       5. The searchlight signal of claim 1 wherein said reflector is made of nickel in which said inner surface is coated with rhodium. 
     
     
       6. A railroad searchlight apparatus for emitting a light signal of one of a plurality of colors, wherein the apparatus comprises: reflector means for reflecting emitted light;   illuminant means, positioned within said reflector means, for emitting the light signal of one of the plurality of colors to be reflected therefrom said reflector means;   power supply means for energizing said illuminant means, whereby said illuminant means is electrically coupled to said power supply means;   light detection means for detecting the reflected light signal and electrically providing a detection signal;   color filter means for filtering a predetermined color of light signal to be detected by said light detection means, wherein said color filter means is positioned between said reflector means and said light detection means; and   electrical signal generating means for generating an electrical identifying signal related to the predetermined color detected through said color filter by said light detection means.   
     
     
       7. The railroad searchlight apparatus of claim 6, wherein said reflector means is geometrically shaped to have a focal point and has an inner surface of reflective material. 
     
     
       8. The railroad searchlight apparatus of claim 7, wherein said illuminant means is positioned at said focal point of said reflector means, thereby to maximize reflection by said reflector means of the light signal emitted from said illuminant means. 
     
     
       9. The railroad searchlight apparatus of claim 8, wherein said illuminant means is at least one light emitting diode that emits light in response to electrical power. 
     
     
       10. The railroad searchlight apparatus of claim 9, wherein said light emitting diode has a plurality of semiconductor junctions of different colors, wherein each junction has individual lead wires, and wherein each junction, when electrically energized, emits colored light. 
     
     
       11. The railroad searchlight apparatus of claim 10, wherein said light emitting diode is a rainbow LED. 
     
     
       12. The railroad searchlight apparatus of claim 6, wherein said power supply means is a variable-current power source. 
     
     
       13. The railroad searchlight apparatus of claim 6, wherein said light detection means is at least one photovoltaic cell that generates voltage according to light detected through said color filter means. 
     
     
       14. The railroad searchlight apparatus of claim 6, wherein said light detection means is at least one phototransistor that conducts electrical current according to light detected through said color filter means. 
     
     
       15. The railroad searchlight apparatus of claim 6, wherein said light detection means is at least one photodiode that conducts electrical current according to light detected through said color filter means. 
     
     
       16. The railroad searchlight apparatus of claim 7, wherein said reflector means is manufactured of nickel in which said inner surface is coated with rhodium.